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A Characterization String Controls Functionality in Embedded Controllers

IP.com Disclosure Number: IPCOM000123613D
Original Publication Date: 1999-Feb-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 1 page(s) / 30K

Publishing Venue

IBM

Related People

Duron, MC: AUTHOR [+5]

Abstract

Embedded controllers frequently contain their programs within themselves in some sort of read only memory (ROM) rather than in external random access memory (RAM). Also they are usually soldered on a circuit board. These conditions make it difficult to change the controller's function.

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A Characterization String Controls Functionality in Embedded Controllers

   Embedded controllers frequently contain their programs
within themselves in some sort of read only memory (ROM) rather than
in external random access memory (RAM).  Also they are usually
soldered on a circuit board.  These conditions make it difficult to
change the controller's function.

   One solution that we have employed is to send an array of
parameters called a "characterization string" to the controller
shortly after power-up and at any desired time thereafter.  This
string sets control parameters for certain operations and can be
more easily changed than the program in the controller.

   A well designed program will have a default behavior but
will permit the characterization string to modify that behavior in
important ways that weren't fully envisioned when the program was
written.  Some examples are:
  1.  Setting alarm threshold values.
  2.  Setting scanning sequences and timings.
  3.  Setting the number of and/or addresses of devices or
      values to scan.
  4.  Informing what action to take when thresholds are crossed.
  5.  Setting permission/denial to perform certain functions.
      This could include debug functions.

   The advantage to this approach is greater flexibility
and functionality without the cost of field replacement of
controllers.